package com.cloud.sms.utils;

import java.security.MessageDigest;

import org.apache.commons.lang.StringUtils;

/**
 * 字符串处理的工具类
 * 
 * @author ruanpeng
 * @since 1.0
 */
public class StringCoreUtils {

    public static String str;

    public static final String EMPTY_STRING = "";

    private final static String[] hexDigits = { "0", "1", "2", "3", "4", "5", "6", "7", "8", "9", "A", "B", "C", "D",
            "E", "F" };

    /**
     * 如果字符串的最后一位为英文逗号，则将其去掉
     * 
     * @param str
     *            需要处理的字符串
     */
    public static String removeLastComma(String str) {
        if (StringUtils.isNotEmpty(str)) {
            char ch = str.charAt(str.length() - 1);
            if (ch == ',') {
                str = str.substring(0, str.length() - 1);
            }
        }
        return str;
    }

    /**
     * @describe 产生注册用户的初始密码
     * 
     * @auther ruanpeng
     * @date 2014年7月19日
     * @return
     */
    public static String generateSixDigits() {
        String s = "";
        int temp = 0;
        while (s.length() < 6) {
            temp = (int) (Math.random() * 10);
            if (temp == 4 || temp == 7) {
                continue;
            }
            s += temp;
        }
        return s;
    }

    private static String byteToHexString(byte b) {
        int n = b;
        if (n < 0)
            n = 256 + n;
        int d1 = n / 16;
        int d2 = n % 16;
        return hexDigits[d1] + hexDigits[d2];
    }

    /**
     * 转换字节数组为16进制字串
     * @param b 字节数组
     * @return 16进制字串
     */
    public static String byteArrayToHexString(byte[] b) {
        StringBuffer resultSb = new StringBuffer();
        for (int i = 0; i < b.length; i++) {
            resultSb.append(byteToHexString(b[i]));
        }
        return resultSb.toString();
    }

    public static String MD5Encode(String origin) {
        String resultString = null;
        try {
            resultString = new String(origin);
            MessageDigest md = MessageDigest.getInstance("MD5");
            resultString = byteArrayToHexString(md.digest(resultString.getBytes()));
        } catch (Exception ex) {
        }
        return resultString;
    }

    public static void main(String[] arg) throws Exception {
        System.out.println("===============" + StringCoreUtils.removeLastComma("dd,,,,"));
    }
}
